Honkai: Star RailRuan MeiBest build, teams and other guides

Ruan Mei is an exceptional support character. She is able to effortlessly buff the whole team’s DMG and increase everyone’s Break Efficiency with her Skill, something no other character is currently able to do. Her Ultimate increases all allies’ RES PEN and is able to delay the enemies again once their Weakness Break ends. She’s even got free bonus Break damage from her Talent that activates whenever allies Break an enemy, and the Talent itself provides a small but permanent SPD boost to all other characters in the party.

The definitely sane, definitely not megalomaniacal Genius Society member, Ruan Mei, is a fairly ridiculous character in the game. She is our very first support character to increase the Weakness Break Efficiency of characters; you know that one Nihility blessing in the Simulated Universe? Night Beyond Pyre, the one that increases Break Efficiency by 30%? Yeah, well, Ruan Mei can increase that by 50% and also have it permanently active.

Ruan Mei’s Skill gives her a buff called Overtone, lasting for 3 turns. This ticks down at the start of her turn. While she has Overtone, all allies’ DMG increases by 32% and Weakness Break Efficiency increases by 50%. This is kind of absurd already given that the application of this buff is entirely effortless, and having it last for 3 turns means that Ruan Mei has plenty of time to recover the SP she spent setting it up and then some. Weakness Break Efficiency is exceedingly powerful. Enemies take slightly reduced damage from all sources while they are not Broken, and this gets removed once they do get Broken, so if you’ve ever wondered why a Broken enemy seems to be taking so much more damage, this is why. 

Usually, there is not a large window of opportunity to take advantage of this state, and it may be preferable to hold off on using big hitting abilities until after the enemy has recovered from Break so as to resume dealing Toughness damage. With this Skill’s effects active, you not only get enemies into that state faster, but it’s easier to repeatedly get them to that state even with weaker hitting attacks, meaning you’re more able to land those huge hits during the enemies’ most vulnerable period.

Ruan Mei’s Ultimate deploys a field for 2 turns, and this also ticks down at the start of her turn. While the field is active, all allies get 25% All-Type RES PEN. If you’ve been around for a while, or if you’re an avid user of Seele, you should understand how rare and powerful Resistance Penetration is by now. 25% is ridiculous, and with a 2-turn duration based on Ruan Mei’s turns, it’s extraordinarily easy to abuse this to the player’s benefit with faster characters or with turn manipulation.

In addition to this, ally attacks within the field apply a debuff to enemies called Thanatoplum Rebloom to enemies they hit. This effect triggers when an enemy attempts to recover from Weakness Break, extending their Weakness Break and delaying their action by 20% of Ruan Mei’s Break Effect plus 10%. This re-Break will also deal 50% of Ruan Mei’s Ice Break DMG. This works in tandem with her Skill to just bully enemies; you Break them faster with the Break Efficiency and then get to keep them Broken for longer, all while benefiting from the DMG bonuses and RES PEN. Important to note that Thanatoplum Rebloom can only trigger again after the enemy has fully recovered from Weakness Break. 

The buffs she provides are already highly impressive even without considering the bonus provided by the Break extension, but with her Talent she provides even more benefits, and she can even contribute some damage of her own. She permanently increases all other teammates’ SPD by 10%, and whenever an ally Breaks an enemy, Ruan Mei will instantly deal damage equal to 120% of her Ice Break DMG. This is not a follow-up attack, this damage is inflicted alongside the Break damage of the ally inflicting Break.

A 10% SPD boost is just about enough to be significant and to meet specific SPD thresholds for characters. However, being able to contribute Break damage without even needing to be the one to Break enemies is ridiculously good, especially as it’s actually a higher multiplier if you let other allies do it for you; this solves the biggest problem with building for Break Effect which is that if you’re not the one to Break enemies, that stat is functionally useless for you. For Ruan Mei, this is most assuredly not the case, so don’t be surprised to be seeing light blue damage numbers in the five-digit range showing up alongside Breaks later on.

It’s clear by now that Ruan Mei benefits the Break playstyle significantly and also benefits from Break Effect% herself as she has so many ways to utilise it. With her Bonus Ability Traces, Ruan Mei reaches a new height that makes her supportive capabilities begin to approach the omnipresent power of Bronya. A2 increases all allies’ Break Effect by 20%, and A4 will regenerate 5 Energy for Ruan Mei at the start of her turn.

A6 is where the big money is; in combat, for every 10% Break Effect that Ruan Mei has that exceeds 120%, her Skill’s DMG bonus increases by an additional 6%, up to a maximum of 36% extra. That means that if you can reach at least 180% Break Effect, Ruan Mei’s Skill is now providing a ridiculous 68% DMG bonus to all allies in addition to its already powerful 50% Break Efficiency. While it is no small feat to achieve such a high Break Effect stat, the mere fact that it’s possible to do so puts Ruan Mei’s supportive capabilities right at the top alongside Bronya and Tingyun.

Eidolon-wise, it’s complete overkill in all cases. E1 is great value because it also gives allies a 20% DEF ignore during the Ultimate, but again, it’s opulence to excess. 

Ruan Mei is very good at facilitating double carry comps, as being able to buff everyone on the team with no effort means that it’s quite easy to keep two damage dealers strong throughout a fight, especially with Ruan Mei’s excellent SP economy. This means that in Kafka DoT teams and Topaz follow-up teams, Ruan Mei is poised to be the leading lass in terms of Harmony supports, and the improvement from including her will be extremely stark.

Where Ruan Mei shines though are the Break teams - pair her with the Harmony Trailblazer and you get yourself the core of the Super Break/Break team. While Firefly and Rappa are the two premium Super Break damage dealers often paired with the Ruan/HMC core, you have basically play any other DPS in the role but Himeko shines the most there and she's a great replacement for those who don't have Firefly and need to tackle Fire-weak content. Super Break teams are currently the strongest archetype together with FUA and Ruan Mei being a core element of it, which makes her worth having on your account.

Usually, I talk about support characters’ damage contribution as ‘non-negligible’ meaning it’s a nice addition to have. Just by being in the team and being well-invested, Breaking of smaller enemies will cause them to simply explode into confetti, again by simply being in the party. The defensive benefits of Breaking enemies quickly and keeping them Broken for longer also cannot be understated, and she can end up greatly assisting lower investment sustain options to keep up by uhh, lemme check my notes here… ‘Murdering things before they can murder you.’ Yeah that sounds about right.

The one truly big downside of Ruan Mei is the obscene investment she demands to reach her peak. As stated earlier, reaching 180% Break Effect is extremely challenging, even with sacrificing your Link Rope. Even if you do reach that amount or close to it, you’ll likely be sacrificing a fair few defensive substats as well, so this is something you need to account for, even if it is partially solved by the increase in Break frequency she provides. Outside of her signature, her Light Cone options are also fairly dismal all things considered, so this should also be taken into account.

Also, stop it, you can’t fix her. Stop it.